ABC | Volume 114, Nº5, May 2020

Original Article Ribeiro Junior & Fernandes Effect of Activity on Hypertension Arq Bras Cardiol. 2020; 114(5):755-761 Statistical analysis All variables went through a descriptive analysis and their frequencies were verified. For continuous variables, measures of central tendency, dispersion and position were provided. The HBP prevalence ratio, according to the independent variables, were was initially calculated in the univariate analysis. In the multivariate analysis, the covariables entered the block models, and PA was considered as a main independent variable with three strata: active in the three forms, active in two forms, and inactive or active in one form. The reference group consisted of active individuals in the three PA forms. The selection of covariables for entry into the multivariate models was based on the theoretical and biological plausibility, and on the gross association strength of the univariate analysis. The Cox regression model was used for cross-sectional studies. 17 Interaction was tested using an additive model of the three PA forms for the occurrence of HBP. The study population, consisting of a pool of surveys, is not random. Thus, the analyses did not use statistical inference; on the contrary, the final model in the multivariate analysis is presented with all the selected variables, with their respective association measures (Prevalence Ratios). For this reason, they are all kept in the final model. Thus, in this study, procedures compatible with the non-random nature of the population investigated were used, according to an extensive literature on the subject. 18,19 All analyses were done using the Statistical Package for the Social Sciences (SPSS) software, version 24.0. Biases In order to minimize the effect of healthy workers, selected workers who were on medical leave were invited to participate, except when the leave was maternity-related or was due to an injury allegedly unrelated to occupational exposure. In this case, the next one on the list would be selected instead. Information biases were minimized with clarifications being provided to workers. The surveys would be under the responsibility of the Federal University of Bahia, so that it would be impossible for both companies and managers to access individual information. Aspects of research ethics This study was submitted to the Research Ethics Committee of the Federal University of Bahia and approved under opinion No. 1,621,917. Subjects were notified about the objectives of the research and all participants signed an Informed Consent Form. Results A total of 1,070 workers were studied, of which 842 (78.7%) were men. The prevalence of HBP was 24%. Workers who did not complete High School made up 46% of the population, 82% had stable partners, 63% had daily working hours with shift schedules. Those who smoke or have smoked accounted for 26%, and 42% of the population consumed alcohol more than once a week. Overweight was present in 43% of the subjects. In PA variables, 47% and 61% of the population had low PA-O and PA-L levels, respectively; 28% were not involved in PA-D. Age and BMI had the greatest factor associated with HBP in the univariate analysis (PR = 2.9 and PR = 2.8, respectively). The following also had strong association: gender (PR = 1.95), PA-D (PR = 1.62) and type of workday (PR = 1.60) (Table 1). The prevalence of HBP by age range was: <35 years (n = 713 individuals) 16% of HBP, 35-44 years (n = 262) 37%, 45-54 years (n = 81) 51%, and for > 54 years (n = 7) individuals, the prevalence was 43%. The frequency of HBP for each one of the PA strata was: 16% for individuals who were active in the three forms, 39% for those who were active in two forms, and 45% for individuals who were inactive or active in only one form (data not shown). Table 2 shows the multivariate analysis, with the main independent variable, PA, in its combinations. Model 1 shows the gross association between PA and HBP. In model 2, the main independent variable is adjusted by sociodemographic variables. And in model 3, an additional adjustment is made for lifestyle variables, when an adjustment of 11% in the main association is observed. The entry of occupational variables in model 4 practically did not change the PR of the main association. Active individuals in two of the three forms, and inactive or active individuals in only one form of PA had a PR of 1.25 and 1.62, respectively. Overweight (PR: 2.26), age > 31 years (PR: 2.10) and male gender (PR: 1.62) covariables maintained their association with HBP in the final model. No interaction was found in the additive model between the three forms of PA for the occurrence of HBP. Discussion PA accumulation in PA-O, PA-D and PA-L forms can lead to HBP improvements. Being active in one or none of the three forms of PA demonstrated a greater positive association with the outcome: 62% more HBP compared to those who are active in the three forms. These findings contribute to the literature on the role of insufficient PA as a modifiable risk factor for HBP and calls into question the isolated role of PA-L as a strategy to control this condition. Regarding color or race, the strong miscegenation of the population in Bahia can represent a limitation to investigate its association with HBP. As described by other authors, 20 the probable homogenization of ethnical groups, due to strong miscegenation, should play a role in the result, which revealed an almost equal prevalence of HBP among the “black” and “non-black” groups in this population. 21,22 According to this explanatory hypothesis, a multicenter HBP study which, in addition to including servers from the Federal University of Bahia also included servers from five other institutions in different states in Brazil, 23 found a strong association of this variable with HBP, whose prevalence was higher among Black people, followed by Brown people, with the lowest prevalence among Caucasians. The association of HBP with age and gender was very consistent with the literature. 11,23-26 The studied population was composed of 79% young men, with a mean age of 32 years. Men in this stage of life are seen to have higher 757